The objective of this project is to use a 2D area detector called Acousto-Optic (AO) sensor to provide an acoustic output monitoring method for HIFU transducers, where the need for two separate methods, radiation force balance and hydrophone scanning, is circumvented. The AO sensor provides an instant 2D image of the radiated HIFU field, which currently requires the very slow point-by-point scanning of a needle hydrophone by a trained operator. Unlike the radiation force balance, the AO sensor provides a direct measure of the acoustic intensity as opposed to just total power. Successful completion of this work will provide a superior method for monitoring acoustic output HIFU transducers, which is critical for ensuring correct ultrasound dose delivery by the HIFU transducer for effective cancer treatment and minimizing collateral damage to healthy tissue. PUBLIC HEALTH RELEVANCE: The successful development of the proposed AO sensor based acoustic output monitoring device could enable routine, on-site assessment of HIFU transducer performance, which is imperative to insure correct dose delivery for HIFU cancer treatment. Current practice of using a combination of hydrophone and radiation force balance methods to establish HIFU transducer output are laboratory based, and do not lend themselves for on-site assessment of HIFU transducers.